The device of this invention relates to the field of vegetable dewatering. Specifically the device of this invention by a unique and simple design dewaters only the outer surface layers of the vegetable material. This process of dewatering greatly improves the shelf life of the vegetable matter while at the same time greatly reducing the period required to re-hydrate the vegetable so that it may be used in salads and so forth, principally in the fast food industry.
The inventor knows of no prior art which accomplishes the function of his invention in the same manner and by use of the same structure.
The inventor finds no instance in the following patents of the combination of air jets and vacuum along with an absorbent surface that he discloses. The closest reference is the prior art disclosed in the Cothran U.S. Pat. No. 2,472,794. Columns 3 and 4 Cothran do discuss the use of blasts of air along with contact to an absorbent material (with no vacuum) but Cothran teaches that these methods are ineffective. Cothran itself relies not upon concentrated air blasts but on air blown by a fan through an open hood and there is no absorbent material or vacuum chamber. Cothran does not disclose any references beyond those in columns 3 and 4, which Cothran says are ineffective, that show the use of a blast of air in conjunction with absorbent material. Cothran does not anywhere disclose the use of a vacuum chamber.
The Prater U.S. Pat. No. 3,113,875 has a good many air ducts but no blast except in FIG. 4 where there is no mechanical conveyor. The dried onions are conveyed by the air stream in that figure. Where there are conveyors there is no absorbent material and no vacuum chamber. Fouineteau U.S. Pat. No. 3,885,321, is simply a spin dryer. The Yamazaki U.S. Pat. No. 4,059,046, is not a dryer at all. Conveyors carry snack food through a deep fat frying tank and then through a cooler with the entire operation being conducted in a vacuum chamber. The only reference to drying is before the material reaches the apparatus. The Bingham U.S. Pat. No. 4,114,286 is yet another spin dryer. The Rose U.S. Pat. No. 4,352,249, merely uses a hood to direct curtain-like air streams. Probably the best drawing is a FIG. 6, which is described at column 5. The fruit is not sliced but has intact skins so that the drying problem is substantially different from that present with sliced fruit or vegetables. There is a discussion of slightly lower pressure in the drying chamber but there is no low pressure chamber below an absorbent surface to pull water through it, and no sliced work pieces which are exposed to air jets above and a vacuum chamber below the conveyor. In this prior art patent any vacuum disclosed surrounds the conveyor.